/*
* RequestHeader.java February 2001
*
* Copyright (C) 2001, Niall Gallagher <niallg@users.sf.net>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package org.simpleframework.http;
import java.util.List;
import java.util.Locale;
/**
* This is a <code>Header</code> object that is used to represent a basic form
* for the HTTP request message. This is used to extract values such as the
* request line and header values from the request message. Access to header
* values is done case insensitively.
* <p>
* As well as providing the header values and request line values this will also
* provide convenience methods which enable the user to determine the length of
* the body this message header prefixes.
*
* @author Niall Gallagher
*/
public interface RequestHeader extends RequestLine {
/**
* This method is used to get a <code>List</code> of the names for the
* headers. This will provide the original names for the HTTP headers for
* the message. Modifications to the provided list will not affect the
* header, the list is a simple copy.
*
* @return this returns a list of the names within the header
*/
List<String> getNames();
/**
* This can be used to get the integer of the first message header that has
* the specified name. This is a convenience method that avoids having to
* deal with parsing the value of the requested HTTP message header. This
* returns -1 if theres no HTTP header value for the specified name.
*
* @param name
* the HTTP message header to get the value from
*
* @return this returns the date as a long from the header value
*/
int getInteger(String name);
/**
* This can be used to get the date of the first message header that has the
* specified name. This is a convenience method that avoids having to deal
* with parsing the value of the requested HTTP message header. This returns
* -1 if theres no HTTP header value for the specified name.
*
* @param name
* the HTTP message header to get the value from
*
* @return this returns the date as a long from the header value
*/
long getDate(String name);
/**
* This is used to acquire a cookie using the name of that cookie. If the
* cookie exists within the HTTP header then it is returned as a
* <code>Cookie</code> object. Otherwise this method will return null. Each
* cookie object will contain the name, value and path of the cookie as well
* as the optional domain part.
*
* @param name
* this is the name of the cookie object to acquire
*
* @return this returns a cookie object from the header or null
*/
Cookie getCookie(String name);
/**
* This is used to acquire all cookies that were sent in the header. If any
* cookies exists within the HTTP header they are returned as
* <code>Cookie</code> objects. Otherwise this method will an empty list.
* Each cookie object will contain the name, value and path of the cookie as
* well as the optional domain part.
*
* @return this returns all cookie objects from the HTTP header
*/
List<Cookie> getCookies();
/**
* This can be used to get the value of the first message header that has
* the specified name. The value provided from this will be trimmed so there
* is no need to modify the value, also if the header name specified refers
* to a comma separated list of values the value returned is the first value
* in that list. This returns null if theres no HTTP message header.
*
* @param name
* the HTTP message header to get the value from
*
* @return this returns the value that the HTTP message header
*/
String getValue(String name);
/**
* This can be used to get the values of HTTP message headers that have the
* specified name. This is a convenience method that will present that
* values as tokens extracted from the header. This has obvious performance
* benefits as it avoids having to deal with <code>substring</code> and
* <code>trim</code> calls.
* <p>
* The tokens returned by this method are ordered according to there HTTP
* quality values, or "q" values, see RFC 2616 section 3.9. This also strips
* out the quality parameter from tokens returned. So "image/html; q=0.9"
* results in "image/html". If there are no "q" values present then order is
* by appearance.
* <p>
* The result from this is either the trimmed header value, that is, the
* header value with no leading or trailing whitespace or an array of
* trimmed tokens ordered with the most preferred in the lower indexes, so
* index 0 is has highest preference.
*
* @param name
* the name of the headers that are to be retrieved
*
* @return ordered array of tokens extracted from the header(s)
*/
List<String> getValues(String name);
/**
* This is used to acquire the locales from the request header. The locales
* are provided in the <code>Accept-Language</code> header. This provides an
* indication as to the languages that the client accepts. It provides the
* locales in preference order.
*
* @return this returns the locales preferred by the client
*/
List<Locale> getLocales();
/**
* This is used to see if there is a HTTP message header with the given name
* in this container. If there is a HTTP message header with the specified
* name then this returns true otherwise false.
*
* @param name
* the HTTP message header to get the value from
*
* @return this returns true if the HTTP message header exists
*/
boolean contains(String name);
/**
* This is a convenience method that can be used to determine the content
* type of the message body. This will determine whether there is a
* <code>Content-Type</code> header, if there is then this will parse that
* header and represent it as a typed object which will expose the various
* parts of the HTTP header.
*
* @return this returns the content type value if it exists
*/
ContentType getContentType();
/**
* This is a convenience method that can be used to determine the length of
* the message body. This will determine if there is a
* <code>Content-Length</code> header, if it does then the length can be
* determined, if not then this returns -1.
*
* @return the content length, or -1 if it cannot be determined
*/
long getContentLength();
/**
* This method returns a <code>CharSequence</code> holding the header
* consumed for the request. A character sequence is returned as it can
* provide a much more efficient means of representing the header data by
* just wrapping the consumed byte array.
*
* @return this returns the characters consumed for the header
*/
CharSequence getHeader();
/**
* This method returns a string representing the header that was consumed
* for this request. For performance reasons it is better to acquire the
* character sequence representing the header as it does not require the
* allocation on new memory.
*
* @return this returns a string representation of this request
*/
@Override
String toString();
}